Regenerative heat exchangers



July 23, 1963 H. H. L. RITZ 3,098,521

REGENERATIVE HEAT EXCHANGERS Filed July 20, 1955 7 Sheets-Sheet 1 July 23, 1963 H. H. L. RITZ 3,098,521

REGENERATIVE HEAT EXCHANGERS Filed July 20, 1955 7 Sheets-Sheet 2 Z J 3! E July 23, 1963 H. H. RlTZ 3,098,521

REGENERATIVE HEAT EXCHANGERS Filed July 20, 1955 7 Sheets-Sheet 3 July 23, 1963 H. H. L. RlTZ 3,

REGENERATIVE HEAT EXCHANGERS Filed July 20, 1955 '7 Sheets-Sheet 4 July 23, 1963 H. H. L. RlTZ 3,

REGENERATIVE HEAT EXCHANGERS Filed July 20, 1955 7 Sheets-Sheet 5 1/," 5/ if? 24/ w July 23, 1963 H. H. L. RlTZ REGENERATIVE HEAT EXCHANGERS 7 Sheets-Sheet 7 Filed July 20, 1955 United States Patent 3,698,521 REGENERATIVE HEAT EXCHANGERS Hugo Heinrich Ludolf Ritz, Newcastie-upon-Tyne, England, assignor to Q. A. Parsons & Company Limited, Newcastie-upon-Tyne, England Filed July 20, 1955, Ser. No. 523,244 Claims priority, application Great Britain Aug. 9, 1954 3 Claims. (Cl. 165-7) The invention relates to a valve arrangement and is particularly though not exclusively concerned with the application of such an arrangement to a regenerative heat exchanger of the kind in which fluids in heat exchanging relationship alternately impart heat to and absorb heat from a matrix under the control of the valve arrangement.

According to the bro-ad aspect of the invention a valve arrangement for controlling the flow of at least one fluid comprises a casing having at least two portions of different cross-sectional dimensions each portion having ports for flow of fluid therethrough, a movable tubular valve element positioned within the casing and having openings at each end thereof and longitudinally arranged portions of cross section appropriate for sliding co-operation with the casing portions to open and close the ports therein.

In a preferred form of the valve arrangement the easing and the valve element each have two portions of smaller cross section and a portion of larger cross section therebetween. The valve elements may be arranged to reciprocate.

In a further preferred form of the invention two valve elements each arranged within its own casing are interconnected for simultaneous operation.

As aforesaid the valve arrangement according to the invention has a particular application in regenerative heat exchangers one form of which is described in my copending application No. 359,182 in which the heat exchanger. comprises a heat storing matrix and a sleeve valve arranged to control the flow through the matrix of hot and cold fluids between which heat exchange is to occur, the matrix being constructed in two portions spaced apart from each other within a casing on either side of a centre-line thereof, the arrangement being that the hot fluid is admitted between the matrix portions and substantially the whole of the hot fluid is caused to flow through at least one of the matrix portions outwardly of the casing to an end outlet thereof and that the cold fluid is admitted to at least one of the matrix portions at an end inlet of the casing and substantially the whole of the cold fluid is caused to flow inwardly of the casing through the matrix portions, to an outlet between the matrix portions, the matrix portions being submitted, under the control of the sleeve valve, to the passage therethrough of the hot and cold fluids alternately.

The heat exchanger described in that application con sists of a single sleeve moving so as to control the inlets and outlets in such a way that while one matrix portion is being submitted to the hot fluid the other portion is being submitted to the cold fluid. In an alternative arrangement both matrix portions are submitted to one fluid at the same time and then in turn tothe other fluid.

Forms are also described therein in which the matrix portions move with the sleeve or are stationary.

When such heat exchangers are required to handle large mass flows the use of one sleeve to control the two matrix portions means that the port areas must be of a similar size the size being based on the maximum volume of the fluid flowing therethrough and as a result the problem arises of keeping down the size of the regenerator especially the moving parts and of keeping distortion to a minimum.

Patented July 23, 1963 Ice An object of the invention is to provide a sleeve valve operated regenerative heat exchanger suitable for a large range of mass flows which will tend to overcome these difliculties.

According to an embodiment of the invention a regenerative heat exchanger comprising a heat storing matrix and a sleeve valve arrangement for controlling the flow through the matrix of relatively hot and cold fluids between which heat exchange is to occur, the matrix be ing constructed in two portions spaced apart from each other within a housing and having inlets and outlets so arranged that the hot fluid is admitted to at least one of the matrix portions through an inlet positioned therebetween and substantially the whole of the hot fluid is caused to how through the matrix portion outwardly of the housing to an end outlet thereof and that the cold fluid is admitted to at least one of the matrix portions through an inlet at an end of the housing and substantially the whole of the cold fluid is caused to flow inwardly of the housing through the matrix portion to an outlet between the matrix portions, and the sleeve valve arrangement comprising two sleeve valves interconnected for simultaneous operation, one sleeve valve controlling the inlet to and the outlet from one matrix portion of fluid to be heated whilst the other sleeve valve controls the inlet to and outlet from the other matrix portion of fluid to be cooled, each sleeve valve including a hollow tubular sleeve having end portions and a central portion of larger diameter than the end portions and co-operating with a similarly shaped casing having ports positioned in the flow paths of the fluids and arranged to be covered or uncovered by the sleeve.

Two embodiments of the invention as applied to a regenerative heat exchanger will now be described by way of example with reference to the accompanying drawings in which:

FIGURE 1 shows a general arrangement in section of a first embodiment of the heat exchanger in which two sleeve valves are in a common housing;

FIGURE 2 shows the housing of the heat exchanger in half section;

FIGURE 3 shows an end view of the housing in half section on line 22 of FIGURE '2;

FIGURE 4 shows in section an end cover;

FIGURE 5 shows an end view of FIGURE 4 looking in the direction of the arrow F.

FIGURE 6 shows an end view of FIGURE 4 looking in the direction of the arrow G.

FIGURE 7 shows a section on line 77 of FIGURE 4;

FIGURE 8 shows in section one of the sleeves;

FIGURE 9 shows a section through a lubricating boss;

FIGURE 10 shows a section on line 1010 of FIG- URE 8;

FIGURE 11 shows a section through a second embodiment of the invention in which the sleeve valves are in separate housings;

FIGURES l2 and 13 show two extreme positions of the sleeves during operation; and

FIGURE 14 illustrates a suitable control mechanism.

In carrying the invention into effect in one form by way of example namely the form in which the two sleeves are in a common housing and referring first of all to FIG- URE 1, a housing 1 is open at each end and houses in its central portion two ported cylinders 2 and 3 which form sealing surfaces for the central portions of the sleeves. End plates 4 and 5 are bolted to each end of the housing. Formed integrally with each end plate are two ported cylinders of smaller diameter than the centrally situated ported cylinders 2, and 3. Cylinders 6 and 7 are associated with end plate 4 whilst cylinders 8 and 9 are associated with end plate 5. The end cylinders 6 and 7 and 8 and 9 form sealing surfaces for the end portions u of the sleeves and extend inside the housing to within a short distance of central cylinders 2 and 3, end cylinders 6 and 8 being in axial alignment with central cylinder 2 whilst end cylinders 7 and 9 are in axial alignment with central cylinder 3. A sleeve 10 consisting of a hollow tube having an enlarged central portion 10a slides with its ends 10b, 100, in cylinders 6 and 8 respectively whilst the central portion 10a slides in cylinder 2. Similarly sleeve '11 having an enlarged portion 11a slides with its ends 11b, 11c, in cylinders 7 and 9 respectively whilst its central portion slides in cylinder 3.

A matrix portion 12 consisting of wire gauze, mesh or corrugated sheets is inserted in a space between cylinders 6 and 7 and the housing 1 in such a way that, looked at in end elevation, it has a shape conforming to that of the housing 1. A matrix portion 13 is arranged in similar fashion at the other end of the housing.

The matrix portions may, however, be arranged to fully surround each sleeve.

The matrix 12 is enclosed at its outer periphery by a radiation shield 14 which is separated from the housing 1 by spacers 15 thus keeping a layer of insulating air between the shield and housing 1. -A similar shield 16 is arranged at the outer periphery of matrix 13.

The heat exchanger operates in the following manner when used to preheat air in a gas turbine plant:

Cold high pressure air leaving the compressor on its way to a combustion chamber is conducted to the heat exchanger via inlet A and, in the position of the sleeves shown, it passes through the sleeve .10 for its full length and then passes through ports 17 in cylinder 8 entering space 18 prior to entry into matrix 13 which has previously been heated. in the matrix 13 it receives heat and then enters space 19 from which space it passes through ports '20 in a liner 21 of central cylinder 2 and thence through ports 22 in cylinder 2 coincident with ports in liner 21 to enter space 23 from which space it leaves the heat exchanger via a duct, not shown in this figure, but which is shown in FIGURE 2, item 60, on its way to a combustion chamber.

During the time this is taking place exhaust gases from the turbine are being led into space 24 via an inlet duct not shown in this view, but which can be seen in FIG- URE 2, item 59, from which space the exhaust gases pass through ports '25- in cylinder 3 and then through coincident ports '26 in a liner 27 of cylinder 3, through space 2 8, to matrix 12 where they give up their heat content, thence through ports 29 in cylinder 7 into the centre of the end portion of cylinder 7 from which they pass to outlet B from the heat exchanger.

The sleeves 10 and 11 remain in this position for a predetermined time, which is based on the time taken to effect efficient heat exchange, and are then switched over by means which will be described later to the limit of their travel in the opposite direction, that is to say sleeve 10 moves towards the left of the drawing until its right hand end uncovers ports 30 in cylinder 6 and simultaneously sleeve 11 moves towards the right until ports 31 in cylinder 9 are uncovered.

Air entering the heat exchanger via inlet A can now enter matrix 12 via ports 30 and space 32. After being heated in matrix 12 it enters space 28 from which space it passes through ports 20 and 22 in liner 21 and cylinder 2 respectively into space 23 where it leaves via a duct as before and is conducted to the combustion chamber.

At the same time hot exhaust gas from the turbine is entering space 24 as before, passing through ports 25 and 26, entering space 19 and passing from there into matrix 13 where it gives up its heat content before entering space 18 passing through ports 31 and then flowing through the full length of sleeve 11 to leave the heat exchanger via outlet B.

This completes the cycle and the movement of the sleeves takes place at regular intervals during operation.

4 There is a position during the change over of the sleeves when all the ports are covered but this is only momentary and does not affect the continuous working of the gas turbine plant and means that the heat exchanger, as described, is continuous in operation.

A wall 33 running at right angles to the plane of the paper for the full width of the housing prevents leakage between space 23 and space 24.

Each sleeve has sealing rings 34 fitted in both end and central portions and these sealing rings prevent the leakage of gas between sleeve and containing cylinder.

In the enlarged central portion of each sleeve equally spaced radially extending vanes are formed integrally with the sleeve and terminate in a central hub.

These vanes are indicated at 35 in sleeve 10 and the hub by numeral 36 Whilst the vanes in sleeve 11 are represented by numeral 37 and the central hub by numeral 38.

The inside of each sleeve is kept cool by the cold compressed air in one case, namely that of sleeve 10, whilst the inside of sleeve 11 is kept cool by the cooled exhaust gases from the turbine and the presence of the vanes helps to ensure efiicient distribution of the cool air and gas into the enlarged central portion of each sleeve for cooling purposes.

Radiation shields 39, 40, 41 and 42 backed by films of insulating air also help to keep the sleeves cool by insulalting them from the hot gases from the turbine or the air after it has been heated. Radiation shields may also be provided on the sloping faces of the enlarged portion of each sleeve.

Each sleeve is actuated by an oil operated piston; sleeve 10 being actuated by piston 43 and sleeve 11 by piston 44. A lever 45 rotating about pivot 46 is linked to both pistons so as to synchronise their movement.

Piston 43 consists of an enlarged end 43a, a hollow central portion 43b and a further portion 430 containing an oil passage 47. This end portion 43c passes through hub 36 and is secured to the hub by means of a nut 48 so that movement of the piston 43 causes movement of sleeve 10. The end portion 43a and part of the central portion 43b slide in a cylinder 49 formed integrally with a dished end cover 50 which is bolt-ed to end cover 5 of housing 1.

Piston 44 is similarly constructed, is attached to sleeve 11 and slides in a cylinder 50 formed integrally with a dished end cover 52 which is also bolted to end cover 5.

Attached to end 430 of the piston 43 is a three way metering valve 53 for distributing lubricating oil through pipes indicated by chain lines in sleeve 11 to the sealing rings 34.

A similar valve 54 is fitted to the end of piston 44. In operation lubricating oil, is, in the position of the sleeves shown, admitted under pressure through oil holes (similar .to those shown dotted in sleeve 11) in the cylinder 49 to a space 55 between the sloping face of piston 43a and the head of cylinder 49 thus forcing piston 43 and thence the sleeve :10 towards the left of the drawing. The oil also passes through oil ports 56 into section 43b of piston 43 and then flows through passage 47 to the three way metering valve 53 from which it is conducted via pipes shown in sleeve 11 as a chain line to sealing rings 34 in sleeve 10.

At the instant at which oil is admitted to space 55 in cylinder 49 the oil pressure in space 57 of cylinder 51 is released and the oil allowed to drain out of holes in the cylinder (shown dotted) adjacent to the cylinder head, under the action of part 44a of piston 44 which, due to the linkage with piston 43 by lever 45, now moves towards the right of the drawing moving sleeve 11 with it.

During the reverse operation of the sleeves oil passes through passage 58 in part 44c of piston 44 and enters metering valve 54.

Referring now to FIGURES 2 and 3 an inlet for the hot gas is indicated at 59 whilst an outlet for the preheated air on its way to the combustion chamber is indicated at 60.

Wall 61 which is frusto-conical in form completely surrounds each of the cylinders 2 and 3 and fills the space between these cylinders and the outer wall of the casing 1 thereby sealing the end portion of the casing from the central part except through cylinders 2 and 3.

Turning to FIGURE 4, the end cover shown is suitable for either of the end covers with reference numerals 4 or 5 in FIGURE 1, except that end cover 5 of FIGURE 1 has bolt holes 62 for supporting the pivot for the lever 45.

Turning to FIGURES 5 and 6 the matrix 12 is inserted in space 6-3 being supported between walls 64 and the housing 1, the shape of the matrix conforming to the shape of the housing 1. Wall 65 on FIGURE 4 is also shown.

FIGURE 7 needs no further comment.

FIGURE 8 shows one of the sleeves 10 or 11 in cross section and shows in detail the arrangements for lubricating the sealing rings.

In the central portion of the piston is a hole 66 which is connected to the three way metering valve of the piston as shown in FIGURE -1.

A metering restriction shown dotted in FIGURE 1, is screwed into the hole for the purpose of ensuring that the pressure drops between the three way metering valve and the various sealing rings are equal to ensure equal distribution of the lubricating oil. From the hole 66 the oil enters oil holes 67 from which they enter the grooves for the sealing rings.

The sealing rings in the end portion of each tube are connected to the three way metering valves via bosses 68 and 69. Boss 68 can be seen in this figure but boss 69 can also be seen in FIGURE 9.

The oil is conducted to each of these bosses the details of which are shown in section in FIGURE 9, and passes through a metering restriction screwed into the boss into hole 70 and thence through oil holes 71 to the bottom of the grooves for the sealing rings.

FIGURE 10 also shows the vanes 35 of FIGURE 1 and boss 36.

In the above construction the use of one housing reduces production costs; end covers are identical in construction; sleeves are identical in shape and size, the matrix may be attached to the end cover and can easily be removed for cleaning by removing the end cover; and lubrication of the sealing rings takes place from inside each sleeve which is cooled by either cold or cooled gas; the length of the sealing surfaces may be reduced whereas the sealing rings in the central portion of each sleeve are sealing all the time, the sealing rings at each end of the sleeve are in sealing contact alternately so that with say in all six effective sets of sealing rings only four need to be effectively sealing at any one time.

Referring now to the alternative form of heat exchanger illustrated in FIGURES 1'1-14 and referring first of all to FIGURE 11 the heat exchanger consists of two housings 101 and 10 2 each of which contains a sleeve. Connecting each housing are four ducts 103-6 inclusive.

in the housing 101 is a sleeve 107 which as shown is of smaller diameter than the sleeve in housing 102, is hollow and cylindrical and has a central portion 107a of enlarged diameter. The sleeve 107 slides by means of sealing rings 108 in a cylinder 109 titted into the casing 101. The central portion 107a of the sleeve 107 slides in a cylinder of larger diameter 10% fitted in the centre of the housing 101. The end portions of the sleeve, cover and uncover ports 110 and 111 in the cylinder 10 9 whilst the central portion 107a covers and uncovers ports 1 12 in the cylinder 109a.

In the lower housing 102 is a sleeve 113 of similar shape to sleeve 107 but of larger diameter and which, in its turn consists of two end portions and a central portion 113a of enlarged diameter, the sleeve sliding by means of sealing rings 114 in cylinder 115. The end portions ot the sleeve 1 13 cover and uncover ports 1'16 and 117 in cylinder 1115 Whilst central portion 113a covers and uncovers ports 118 in cylinder a.

Situated between the end portions of cylinder 115 and the outer wall of housing 102 is a matrix or heat accumulating mass 119 in two parts 11 9a and 11911. The matrix is housed between inner and outer cylindrical walls .120 and 121 which are held together by rods 122 which act at the same time as spacers between four layers forming each matrix 11%, 11%. The matrix consists of a multitude ot small parallel channels for the flow of the gases and is arranged in frusto-conical torm.

The outer wall 121 is spaced from the wall of housing 102 to form an annular space 123 for the passage of gases on their way to the matrix. Separating the inner wall from the cylinder 1 15 is an air gap 124 which insulates the Wall from the cylinder.

In operation in a gas turbine plant and referring particularly to FIGURES l2 and 13 and first to FIGURE 12, in that figure air enters the regenerator from the compressor and enters the inside of sleeve 107 flows along the full length of the sleeve and leaves via ports 110 in cylinder 109. It then enters duct 103 and is conveyed to the annular space 123 in housing 102. From here it enters matrix portion 119a via the space 125, flows through the passages of the matrix where it is heated and collected in space 126 which is in communication 'with duct-104. Duct 104- conveys the heated air to space 127 surrounding cylinder F109 trom which the air passes through ports 112 to be collected in annular space 128 from which it is led to the combustion chamber.

At the same time hot exhaust gas from the turbine enters space 129 from whence it flows through ports 118 into space 130 and thence it enters the matrix 11%. The gas gives up its heat content to the matrix and then leaves it, entering space 131 from which it passes through ports 117 in the cylinder into space 132 which is in communication with an exhaust stack.

The sleeves are, after a predetermined time, switched over simultaneously to the position shown in FIGURE 13. When in this position air from the compressor enters the inside of sleeve 107, passes through ports 111, thence through duct 1% and then to annular space 123 surrounding matrix portion 11% from which space it enters space 131, flows through matrix 11912 Where it receives the heat previously given up by the hot gas and then exhausts into space 130 from which space it is led via duct 105 to space 133 and thence through ports 11 2 into space 128 from which it is led to the combustion chamber as before.

At the same time hot exhaust gas from the turbine enters the matrix 1119:; via space 129, ports 1:18 and space 126, gives up its heat and exhausts to atmosphere via space 125, ports 116 and the inside of sleeve 1-13 to space 132.

Operation of the regenerator is effected or maintained by intermittently switching the sleeves simultaneously from one position to the other.

Referring once more to FIGURE 11 the central portion of each sleeve has the tace containing the sealing rings cooled every half cycle by the cooled exhaust gas in the case of sleeve 113 and by the cold air from the compressor in the case of sleeve 107. Ribs 13 4 in each sleeve assist in this cooling by deflecting the flow of gas or air.

The cylinder 115a is insulated tfrom the incoming gases in space 129 by insulation shields and the cylinder 109a in housing 101 by shields \136 from the hot compressed air on its way to the combustion chamber from annular space 128.

Pressure losses at the inlets to the various ports are reduced by cutting away walls defining the entrances to the ports so as to give a nozzle effect.

The temperature distribution in each sleeve is as before symmetrical in that the ends of each sleeve are relatively cool whilst the center portions 107a and 113a are hot. This reduces distortion in the sleeves and in the housing.

Conical walls 137 are attached to housing 102 and to cylinder 115a and separate inlet space 129 from spaces 126 and 130. Being of conical form, the walls exp-and symmetrically and in consequence keep the sleeve accurately centred in cylinder 115a.

The centre part 113a of the sleeve is also insulated against the hot gases in spaces 126, 129 and 130 by in sulation shields 138.

The central part of housing 102 is in two halves and bolted along flanges 139. The housing at this point is protected from the hot gases entering annular space 129 by insulating shield 140 which is spaced from the housing by rings 141 and the spaces filled with insulating material. This central part of housing 102 is also free to expand axially due to clearances not shown between the flange 139 and wall 137.

The switching of the sleeves 107 and 113 from the position shown in FIGURE 12 to the other shown in FIG- URE 13 is effected by the forces exerted on the sleeve by the heat exchanging gases themselves due to the dhference in the dimensions of the sleeves in conjunction with a suitable control mechanism whose tunction is to hold the sleeves in each position shown for a predetermined time and then release them. The control mechanism must also, during movement ensure that the sleeves are synchronised that is to say they each pass through the neutral position at the same time. In other words when sleeve 107 is at the position where ports 112 are cut Off, sleeve 113 should be in the position where ports 118 are cut olf from theflow of the gases.

When the sleeves are in the position shown in FIGURE 12 high pressure air in space 126 exerts a force on sleeve 113 tending to move it towards the right of the drawing. Immediately the control mechanism releases the sleeves, sleeve 113 accelerates towards the right and at the same time sleeve 107 moves towards the left accelerating also but against the force exerted on its central part 107a by the high pressure gas in space 127 which force tends to reduce the acceleration of sleeve 107 and in view of the linked movement, sleeve 113 also.

As each sleeve passes the neutral position the pressure conditions are reversed and the high pressure gas now admitted to space 130 \acts against the movement of the sleeve 113 decelerating it until it stops in the positions shown in FIGURE 13. The sleeves are held in this position for a predetermined time and then released and they move back to the position shown in FIGURE 12 under the action of the forces exerted by the high pressure air.

A suitable control mechanism is shown diagrammatically in FIGURE 14. The matrix, housings 101 and 102, and interconnecting ducts have been omitted and only the sleeves 107 and 113 in their respective cylinders 109 and 115 are shown.

At the left hand end of each housing is fitted a cylinder containing a piston which is hydraulically operated by some substantially incompressible fluid such as oil.

Cylinder 142 is attached to cylinder 109 which in turn is fixed to housing 101 as shown in FIGURE 11. The piston 143 in cylinder 142 is attached to sleeve 107 by rod .144 which may be hollow, the rod being bolted to the central hub in the enlarged portion of the sleeve from which ribs 134 as shown in FIGURE 1 radiate.

A similar cylinder 145 containing piston 146 is attached to cylinder 115 in housing 102 and is similarly attached to the central hub in the enlarged portion 113a of the sleeve 113 by rod 147 Sealing the extreme left hand end of each cylinder 142 and 145 are end covers 148 and 149 respectively.

each housing.

An oil pump 1'50 supplies oil to a continuously rotating rotary valve 151 which supplies oil alternately to that part of each of the cylinders 142, which is on the right hand side of each piston, through ducts 152 and 153. Filling the space in each cylinder between the piston and end the covers 148 and 149 is a further quantity of oil which can be displaced between each cylinder through duct 154 which is always full of oil.

The valve 151 is so constructed that, in the position shown, duct 152 is connected to the oil drain through duct 155 whilst duct 153 is in communication with pump 150.

This condition is maintained for a predetermined length of time which is suflicient to allow adequate heat transfer to take place between the hot gases, the cold high pressure air and the matrix portions.

After this time has elapsed the valve 151 cuts ed the supply of oil to duct 153 from oil pump and puts duct 153 in communication with the drain through duct 155. The sleeve 1 13 then begins to move towards the right under the action of the :forces exerted by the high pressure air on enlarged part 113a as described earlier and in doing so moves piston 146 to the right displacing oil through duct 153 to drain through duct 155. At the same time pump 150 supplies oil through duct 152 to the right hand side of piston 143 forcing it to the left and displacing oil through duct 154 to the left hand side of piston 146 thus ensuring synchronisation of movement between the two.

Any leakage past the pistons 145, 146 which may aifect the volume of oil flowing in duct 154 can be compensated by a system of non-return valves connected to duct 154 for replenishing any oil lost or bleeding off any oil causing an increase in volume. Alternatively the non return valves may be fitted in the pistons themselves.

Such leakage will in most cases however be so small as to have no appreciable reflect on the synchronisation of the sleeves.

According to another method the sleeves are linked mechanically through a rod attached to each sleeve at its ends and pivoted in the centre. The retention of the sleeve in the extreme end conditions may be effected by the hydraulic means.

It can be seen that in both the forms illustrated temperature symmetry is achieved in an axial direction in In each case the central portion of one sleeve controls the inlet of the heat releasing gas before cooling whilst the central portion of the other controls the outlet of the heat absorbing gas after it has been heated. The central portions of the housing are therefore always subject to hot gas. The end portions on the other hand are always cool, one sleeve controlling the admission of the heat absorbing gas before it is heated whilst the other controls the outlet of the heat releasing gas after it has been cooled. This fact coupled with the fact that the sleeves :also act as ducts for cold gas namely cooled heat releasing gas on the one hand and cold heat absorbing gas on the other means that the temperature increases progressively from the ends of the housing towards the centre.

Further the sleeves in both cases are of simple construction, are light and the fact that they contain no ports means that distortion is kept to a minimum.

Other advantages are obtained from a production point of view if the sleeves are identical in size, but this factor may be outweighed by the desirability of making the high pressure sleeve of smaller dimensions when mass flows are very large.

As aforesaid the valve arrangement per se is within the scope of the present invention and the preferred form of the valve arrangement has been described and illustrated in FIGURE 8 whilst a form of valve element is shown in FIGURES 8 and 10".

I claim:

1. A regenerative heat exchanger comprising a heat storing matrix and a sleeve valve arrangement for controlling the flow through the matrix of relatively hot and cold fluids between which heat exchange is to occur, the matrix being constructed in two portions spaced apart from each other within a housing and having inlets and outlets so arranged that the hot fluid is admitted to at least one of the matrix portions through an inlet positioned therebetween and substantially the whole of the hot fluid is caused to flow through the matrix portion outwardly of the housing to an end outlet thereof and that the cold fluid is admitted to :at least one of the matrix portions through an inlet at an end of the housing and substantially the whole of the cold fluid is caused to flow inwardly of the housing through the matrix portion to an outlet between the matrix portions, and the sleeve valve arrangement comprising two sleeve valves interconnected for simultaneous operation, one sleeve valve controlling the inlet to and the outlet from one matrix portion of fluid to be heated whilst the other sleeve valve controls the inlet to and outlet from the other matrix portion of fluid to be cooled, each sleeve valve including a hollow tubular sleeve having end portions and a central portion of larger diameter than the end portions and co-operating with a similarly shaped casing having ports positioned in the flow paths of the fluids and arranged to be covered or uncovered by the sleeve, sealing between the sleeves and their associated casing portions is eifected by means of sealing rings fitted to the sleeves and which said sealing rings are lubricated by oil fed to grooves containing the rings from the inside of the sleeve which is kept cool at all times by cool heat exchanging fluid.

2. A regenerative heat exchanger comprising at least two heat storing matrices and a valve arrangement for controlling the flow of fluids between which heat is to be exchanged, said valve arrangement comprising at least two continuous tubular open-ended valve members having end portions and a portion of enlarged cross-section intermediate said end portions, a casing for each said valve member, said casing having apertured portions arranged for sliding cooperation with said end and enlarged portions respectively of the valve member with which the casing is arranged to cooperate, first flow-path defining means for one of said fluids and extending through an aperture in at least one end portion of one of said casings under the control of the valve member arranged to cooperate therewith to one of said matrices, second flowpath defining means from said one matrix and through an aperture in said enlarged portion of said one casing under the control of said enlarged portion of said one valve member, third flowpath defining means for another of said fluids and extending through an aperture in said enlarged portion of another of said casings, under the control of said enlarged portion of the valve member arranged to cooperate therewith, to another of said matrices, fourth flow-path defining means from said other matrix and through an aperture in at least one end portion of said other casing under the control of said other valve member, said second and third flow-path defining means being positioned wholly outside said valve members, connecting means between said valve members and means to effect simultaneous sliding movement of said valves with respect to said casings.

3. A regenerative heat exchanger comprising at least two heat storing matrices and a valve arrangement for controlling the flow of fluids between which heat is to be exchanged, said valve arrangement comprising at least two continuous t ubul-ar open-ended valve members having end portions and a portion of enlarged cross-section intermediate said end portions, a casing for each said valve member, said casing having apent-ured portions arranged for sliding cooperation with said end and enlarged portions respectively of the valve member with which the casing is arranged to cooperate, first flow-path defining means for one of said fluids and extending through an aperture in at least one end portion of one of said casings under the control of the valve member arranged to cooperate therewith to one of said matrices, second flow-path defining means from said one matrix and through an aperture in said enlarged portion of said one casing under the control of said enlarged portion of said one valve member, third flow-path defining means for another of said fluids and extending through an aperture in said enlarged portion of another of said casings, under the control of said enlarged portion of the valve member arranged to cooperate therewith, to another of said matrices, fourth flow-path defining means from said other matrix and through an aperture in at least one end portion of said other casing under the control of said other valve member, connecting means between said valve members and means to efiect simultaneous sliding movement of said valves with respect to said casings.

References Cited in the file of this patent UNITED STATES PATENTS 2,204,431 Moore et al June 11, 1940 2,737,970 Hasche et a1 Mar. 13, 1956 FOREIGN PATENTS 158,352 Australia Aug. 19, 1954 

1. A REGENERATIVE HEAT EXCHANGER COMPRISING A HEAT STORING MATRIX AND A SLEEVE VALVE ARRANGEMENT FOR CONTROLLING THE FLOW THROUGH THE MATRIX OF RELATIVELY HOT AND COLD FLUIDS BETWEEN WHICH HEAT EXCHANGE IS TO OCCUR, THE MATRIX BEING CONSTRUCTED IN TWO PORTIONS SPACED APART FROM EACH OTHER WITHIN A HOUSING AND HAVING INLETS AND OUTLETS SO ARRANGED THAT THE HOT FLUID IS ADMITTED TO AT LEAST ONE OF THE MATRIX PORTIONS THROUGH AN INLET POSITIONED THEREBETWEEN AND SUBSTANTIALLY THE WHOLE OF THE HOT FLUID IS CAUSED TO FLOW THROUGH THE MATRIX PORTION OUTWARDLY OF THE HOUSING TO AN END OUTLET THEREOF AND THAT THE COLD FLUID IS ADMITTED TO AT LEAST ONE OF THE MATRIX PORTIONS THROUGH AN INLET AT AN END OF THE HOUSING AND SUBSTANTAILLY THE WHOLE OF THE COLD FLUID IS CAUSED TO FLOW INWARDLY OF THE HOUSING ATHROUGH THE MATRIX PORTION TO AN OUTLET BETWEEN THE MATRIX PORTIONS, AND THE SLEEVE VALVE ARRANGEMENT COMPRISING TWO SLEEVE VALVES INTERCONNECTED FOR SIMULTANEOUS OPERATION, ONE SLEEVE VALVE CONTROLLING THE INLET TO AND THE OUTLET FROM ONE MATRIX PORTION OF FLUID TO BE HEATED WHILST THE OTHER SLEEVE VALVE CONTROLS THE INLET TO AND OUTLET FROM THE OTHER MATRIX PORTION OF FLUID TO BE COOLED, EACH SLEEVE VALVE INCLUDING A HOLLOW TUBULAR SLEEVE HAVING END PORTIONS AND A CENTRAL PORTION OF LARGER DIAMETER THAN THE END 